.TH EM_M2 6 "$Revision$"
.ad
.SH NAME
em_m2 \- ACK Modula\-2 compiler
.SH SYNOPSIS
.B ~em/lib.bin/em_m2
.RI [ option ] 
.I source
.I destination
.SH DESCRIPTION
.I Em_m2
is a
compiler, part of the Amsterdam Compiler Kit, that translates Modula-2 programs
into EM code.
The input is taken from
.IR source ,
while the
EM code is written on 
.IR destination .
.br
.I Option
is a, possibly empty, sequence of the following combinations:
.IP \fB\-I\fIdirname\fR
.br
append \fIdirname\fR to the list of directories where definition modules
are looked for.
.PP
When the compiler needs a definition module, it is first searched for
in the current directory, and then in the directories given to it by the
\-\fBI\fR flag
in the order given.
.IP \fB\-M\fP\fIn\fP
set maximum identifier length to \fIn\fP.
The minimum value for \fIn\fR is 14, because the keyword
"IMPLEMENTATION" is that long.
.IP \fB\-n\fR
do not generate EM register messages.
The user-declared variables will not be stored into registers on the target
machine.
.IP \fB\-L\fR
do not generate the EM \fBfil\fR and \fBlin\fR instructions that enable
an interpreter to keep track of the current location in the source code.
.IP \fB\-V\fIcm\fR.\fIn\fR,\ \fB\-V\fIcm\fR.\fIncm\fR.\fIn\fR\ ...
.br
set the size and alignment requirements.
The letter \fIc\fR indicates the simple type, which is one of
\fBw\fR(word size), \fBi\fR(INTEGER), \fBl\fR(LONGINT), \fBf\fR(REAL),
\fBd\fR(LONGREAL), or \fBp\fR(POINTER).
It may also be the letter \fBS\fR, indicating that an initial
record alignment follows.
The \fIm\fR parameter can be used to specify the length of the type (in bytes)
and the \fIn\fR parameter for the alignment of that type.
Absence of \fIm\fR or \fIn\fR causes a default value to be retained.
.IP \fB\-w\fR\fIclasses\fR
suppress warning messages whose class is a member of \fIclasses\fR.
Currently, there are three classes: \fBO\fR, indicating old-flashioned use,
\fBW\fR, indicating "ordinary" warnings, and \fBR\fR, indicating
restricted Modula-2.
If no \fIclasses\fR are given, all warnings are suppressed.
By default, warnings in class \fBO\fR and \fBW\fR are given.
.IP \fB\-W\fR\fIclasses\fR
allow for warning messages whose class is a member of \fIclasses\fR.
.IP \fB\-x\fR
make all procedure names global, so that \fIadb\fR(1) understands them.
.IP \fB\-g\fR
produce a DBX-style symbol table.
.IP \fB\-l\fR
enable local extensions. Currently, there are two local extensions:
procedure constants, and the type LONGCARD.
.IP \fB\-s\fR
make INTEGER ranges symmetric, t.i., MIN(INTEGER) = - MAX(INTEGER).
This is useful for interpreters that use the "real" MIN(INTEGER) to
indicate "undefined".
.IP \fB-R\fR
disable all range checks.
.IP \fB-A\fR
enable extra array bound checks, for machines that do not implement the
EM ones.
.IP \fB-U\fR
allow for underscores within identifiers. Identifiers may not start with
an underscore, even if this flag is given.
.IP \fB-3\fR
only accept Modula-2 programs that strictly conform to [1].
.LP
.SH SEE ALSO
\fIack\fR(1), \fImodula-2\fR(1)
.IP [1]
N. Wirth, \fIProgramming in Modula-2\fP, 3rd edition, Springer Verlag.
.SH DIAGNOSTICS
All warning and error messages are written on standard error output.
.SH REMARKS
Debugging and profiling facilities may be present during the development
of \fIem_m2\fP.